This invention relates to a method of making an optical fiber termination, the optical fiber being secured in a ferrule.
To connect optical fibers with each other, it is generally known to employ a method which fixes the optical fibers 101, 102 into cylindrical rod-like ferrules 103, 104 by use of adhesive, inserts them into a hollow cylindrical alignment sleeve 108, and butts the end surfaces of the optical fibers 101, 102 against each other, as shown in FIG. 7. The end surface of each ferrule 103, 104 and the end surface of each optical fiber 101, 102 are together ground to a convex spherical plane 107 having its apex on the center axis 106 of the optical fiber.
However, in order to shape this convex spherical surface 107, a plurality of grinding steps ranging from rough grinding to finish grinding are necessary. Therefore, this method involves the following problems throughout all the grinding steps:
(1) The ground surfaces must have the same radius of curvature; and PA1 (2) It is extremely difficult to bring the central axis of each ferrule 103, 104, that is, the central axis of each fiber 101, 102, into conformity with the apex of the convex spherical surface.
Further, because the ferrule 103, 104 having the fiber 101, 102 fixed thereto is made of ceramic material and metal material or is made fully of ceramic material, it has high hardness. Since the end surfaces are broad, too, grinding of these surfaces takes a long time in finish grinding and grains extracted in a grinding pan during the grinding operation damage the end surfaces of the fiber 101, 102. Accordingly, a method which is entirely satisfactory in mass-producibility and finish accuracy has not yet been put into practice.
When the fibers 101, 102 are fixed into the ferrules 103, 104, adhesive flowing out from the ends of the ferrules 103, 104 adheres to and hardens on the end surfaces of the ferrules and degradation of the quality of the finished surfaces and damage of the end surfaces occur depending on the amount and shape of the adhesive. Furthermore, this adhesive increases remarkably the necessary finishing time.